@article{fdi:010070018,
  title = {{V}ariable reactivity of particulate organic matter in a global ocean biogeochemical model},
  author = {{A}umont, {O}livier and van {H}ulten, {M}. and {R}oy-{B}arman, {M}. and {D}utay, {J}. {C}. and {E}the, {C}. and {G}ehlen, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he marine biological carbon pump is dominated by the vertical transfer of particulate organic carbon ({POC}) from the surface ocean to its interior. {T}he efficiency of this transfer plays an important role in controlling the amount of atmospheric carbon that is sequestered in the ocean. {F}urthermore, the abundance and composition of {POC} is critical for the removal of numerous trace elements by scavenging, a number of which, such as iron, are essential for the growth of marine organisms, including phytoplankton. {O}bservations and laboratory experiments have shown that {POC} is composed of numerous organic compounds that can have very different reactivities. {H}owever, this variable reactivity of {POC} has never been extensively considered, especially in modelling studies. {H}ere, we introduced in the global ocean biogeochemical model {NEMO}-{PISCES} a description of the variable composition of {POC} based on the theoretical reactivity continuum model proposed by {B}oudreau and {R}uddick (1991). {O}ur model experiments show that accounting for a variable lability of {POC} increases {POC} concentrations in the ocean's interior by 1 to 2 orders of magnitude. {T}his increase is mainly the consequence of a better preservation of small particles that sink slowly from the surface. {C}omparison with observations is significantly improved both in abundance and in size distribution. {F}urthermore, the amount of carbon that reaches the sediments is increased by more than a factor of 2, which is in better agreement with global estimates of the sediment oxygen demand. {T}he impact on the major macronutrients (nitrate and phosphate) remains modest. {H}owever, iron ({F}e) distribution is strongly altered, especially in the upper mesopelagic zone as a result of more intense scavenging: vertical gradients in {F}e are milder in the upper ocean, which appears to be closer to observations. {T}hus, our study shows that the variable lability of {POC} can play a critical role in the marine biogeochemical cycles which advocates for more dedicated in situ and laboratory experiments.},
  keywords = {},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {14},
  numero = {9},
  pages = {2321--2341},
  ISSN = {1726-4170},
  year = {2017},
  DOI = {10.5194/bg-14-2321-2017},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070018},
}